1. Field of the Invention
The present invention relates to a signal detecting method and device, and more particularly, to a detecting method and device for suppressing interference of low-frequency noise.
2. Description of the Prior Art
Signals that are under the influence of low-frequency noise may become distorted. These signals may, for example, be used as the driving signals of a capacitive touch sensor. The capacitive touch sensor may include a plurality of detecting electrodes. If a driving signal is provided to one or more of the detecting electrodes, the detecting electrodes themselves will produce self-capacitive coupling or mutual-capacitive coupling between one another. When an external conductive object approaches or touches the capacitive touch sensor, changes in the capacitive coupling may be created in some of the detecting electrodes. By detecting this change in capacitive coupling, the location of the external conductive object can be determined.
When using an active capacitive pen, the activation time of the capacitive pen and the activation time of the touch sensor may not be the same, so one must be synchronized to the other, including synchronization of their frequencies. As a result, additional cost and time are required for the synchronization of signals. In addition, due to the synchronization requirement of the capacitive pen, it can only be used with specific touch sensors, and cannot be widely applied.
From the above it is clear that prior art still has shortcomings. In order to solve these problems, efforts have long been made in vain, while ordinary products and methods offering no appropriate structures and methods. Thus, there is a need in the industry for a novel technique that solves these problems.